1. Field of the Invention
The general inventive concept of this invention relates to a servo track writer and a chuck thereof, and more particularly, to a chuck structure to fix a disk hub supporting a plurality of disks at two points spaced apart from each other by a certain distance along a central axis of the disk hub.
2. Description of the Related Art
Generally, hard disc drives are auxiliary storage devices used in computers. In such a hard disc drive, a magnetic head is arranged therein to perform operations of reading data written on a disk arranged in the hard disc drive or writing data on the disk while moving along tracks on the disk.
The disk has a plurality of concentric tracks dividing a data area of the disk in a circumferential direction of the disk, and a plurality of sectors dividing each track into a plurality of regions in a radial direction of the disk. Each track region has basic information including, for example, a track number and a sector number, that is, servo information written on a certain portion of the disk. Positioning of the magnetic head is controlled based on the servo information by determining whether or not the magnetic head is positioned at a target track region.
In order to write such servo information on a disk in a process of manufacturing a hard disk drive, a servo track writer is used. An example of a conventional servo track writer is disclosed in Korean Patent No.: 303531 or Korean Patent Publication No.: 10-2000-0056740 published on Sep. 15, 2000. The conventional servo track writer discloses a structure to perform writing of servo information on disks in an individual manner under a condition in which each disk is assembled together with a head arm to be disposed in a casing of an associated hard disk drive. For this reason, there is a limitation in productivity. For eliminating such a limitation, it is necessary to provide a servo track writer to perform writing of servo information on a plurality of disks in a simultaneous manner, prior to assembly of associated hard disk drives. In such a servo track writer, it is particularly important to maintain a central axis of a disk hub, mounted with a plurality of disks, in a state of being aligned with a rotating axis of a spindle motor adapted to rotate the disk hub without being inclined.
Magnetic heads write servo information on the disks. Each of the magnetic heads moves along an associated one of the disks to perform writing of servo information while being spaced apart from the associated disk by a small clearance of, for example, several micrometers. For this reason, the central axis of the disk hub is misaligned with the rotating axis of the spindle motor. Accordingly, there may be a problem in that the disk fluctuates during the rotation thereof so that it may strike the associated magnetic head.